Eutectic Crystallization Activates Solid-State Zinc-Ion Conduction.

Solid-state zinc (Zn) batteries offer a new candidate for emerging applications sensitive to volume, safety and cost. However, current solid polymeric or ceramic electrolyte structures remain poorly conductive for the divalent Zn , especially at room temperature. Constructing a heterogeneous interface which allows Zn percolation is a viable option, but this is rarely involved in multivalent systems. Herein, we construct a solid Zn -ion conductor by inducing crystallization of tailored eutectic liquids formed by organic Zn salts and bipolar ligands. High-entropy eutectic-networks weaken the ion-association and form interfacial Zn -percolated channels on the nucleator surfaces, resulting in a solid crystal with exceptional selectivity for Zn transport (t =0.64) and appreciable Zn conductivity (σ =3.78×10  S cm at 30 °C, over 2 orders of magnitude higher than conventional polymers), and finally enabling practical ambient-temperature Zn/V O metal solid cells. This design principle leveraged by the eutectic solidification affords new insights on the multivalent solid electrochemistry suffering from slow ion migration.